Robots in general are, of course, well known and have been increasingly utilized in industry to produce substantial productivity increases. Such robots have found use in a number of fields and have found particular acceptance in the finishing area where the exact repeatability of the robot provides greatly improved quality, while at the same time removing workers from what is often considered a less than ideal environment. For painting purposes, such robots are programmed by one of two methods. Either they are programmed by entering the various points and paths over which the robot will travel or they are literally taught by attaching a pendant at the arm end next to the spray gun whereby an experienced painter literally leads the end of the robot through the desired path so that the robot records the path and then is able to repeat that path at will. That path may also be later edited if desired.
Electric robots, while desirable in many ways have suffered from a general inability to be programmed by teaching. Such robots typically have a higher speed relatively low-torque motors such that the types of gear reduction utilized do not allow easy movement of the end of the robot for teaching purposes. Of course, hydraulically operated robots have been known and used extensively as well, and while such robots are known for being able to be taught, they are not always desirable for other reasons. Such robots are typified and shown in U.S. Pat. Nos. D 273,300; 4,531,885 and 4,598,601.
It is, therefore, an object of this invention to provide a robot which is extremely compact and provides a most limited footprint in the spray booth and which has an extremely wide envelope. Particularly in the spray painting area, it is extremely desirable for a robot to have as large an envelope of motion as possible. Such spray booths are extremely limited in the amount of space available and, thus, the combination of a unit with an extremely small footprint and large envelope provides an extremely advantageous combination. It is a further object of this invention to provide an efficient and compact counterbalancing mechanism which is easily adjusted depending upon the particular situation and tool being used. It is further an object of this invention to provide an electric robot which has the ability to be easily taught using a teaching pendant or a similar type device. It if further an object of this invention to provide a robot which is easily and inexpensively manufactured and which may be easily maintained under plant conditions.